1. Technical Field
The present invention relates generally to a method for acquiring an image, and an ion beam apparatus.
2. Description of the Related Art
A process of scanning and sweeping an ion beam across a target (a sample), in which a conductor is present on an insulator, to observe or process the sample is used for many applications. For example, there is repair of a mask used to produce a semiconductor device and so on.
The mask has a mask pattern of a conductive material such as a metal on a transparent dielectric substrate such as a glass. The mask screens light in a shape of the mask pattern. The mask pattern has an isolated pattern or the like in which striped lines and spaces arranged vertically and horizontally, or small rectangles are present. In this way, the shape of the mask pattern mostly has pattern edges in all directions. The repair of the mask does not remake a front surface of the expensive mask when there are defects or the like in a pattern of the mask, but repairs only the defects or the like, which is advantageous from an economical and temporal standpoint.
In the repair of the mask, an ion beam is scanned and swept across the pattern edge of the mask in a horizontal or orthogonal direction.
As a similar technology, for example, an X-ray mask examination device for scanning and sweeping across an X-ray mask to acquire or examine (observe) an image is described in Patent Literature 1. It is also described in the X-ray mask examination device that an electron beam is scanned across a pattern edge of a line shape in an orthogonal direction or is scanned and swept across a rectangular mask pattern in a parallel or orthogonal direction.